This invention relates generally to circuit interrupters and more particularly to a multiple pole molded case circuit breaker having an improved electromechanical undervoltage release mechanism for causing tripping of the breaker whenever the line voltage falls below a predetermined level.
Molded case circuit breakers are known throughout the industry as being highly effective circuit protectors which prevent or minimize damage to low voltage electrical circuits and the electrical equipment connected thereto. The circuit breakers generally operate to interrupt the electric circuit whenever overload conditions on the line exceed predetermined safe levels. However, there is another occurrence which occasionally happens, and that involves having a line voltage less than desirable. For example, if the line voltage drops below 35 to 70 percent of normal line voltage, motors and other equipment connected to the line may attempt to run on this less than sufficient voltage, with the result being that the motors and other equipment may overheat. Therefore, it is desirable to provide undervoltage protection which will interrupt the electrical circuit whenever the voltage on the line drops below a predetermined amount.